The Northrop Tacit Blue was a technology demonstrator aircraft created to demonstrate that a stealth low observable surveillance aircraft with a low probability of intercept radar and other sensors could operate close to the forward line of battle with a high degree of survivability.The aircraft made its first flight in February 1982, and subsequently logged 135 flights over a three year period. The aircraft often flew three to four flights weekly and several times flew more than once a day. After reaching about 250 flight hours, the aircraft was placed in storage in 1985. In 1996, Tacit Blue was placed on display at the National Museum of the United States Air Force at Wright Patterson Air Force Base, near Dayton, Ohio. Tacit Blue is on display in the Research and Development Hangar (within the Wright-Patterson Air Force Base perimeter and away from the main National Museum site).
(wikipedia)

About this creation

There is only a single air intake for both reactors, and it is situated on the back of the plane

Nozzles rear are of shape flattened to cool gases at contact of the ambient air.

I think that the SR-71 blackbird's sucessor looks more like the CL-400 Suntan.
If you hadn't already checked Krystek Pietrzak's SR-91, just take a look...
(and sorry for my bad english but I'm french) :)